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By Rambabu Pothina, MELO EDUARDO PIMENTA DE, Rajive Ganguli

 The mining industry is home to a mass of sensor-generated data that are critical to real-time and long-term optimization. This heavy reliance on sensor data has resulted in an undesirable development. The industry is reluctant to verify the accuracy of sensors as it would mean shutting down important processes. Sensors are typically calibrated once a year, if at all. Errors in sensors go undetected until the next calibration or until errors are so gross as to be obvious

By Jens Classen

"GENERAL PROJECT DATA The Sparvo Tunnel belongs to “Variante di Valico” project, a new 65 km highway link between Bologna and Florence, designed to renew the existing A1 route and to connect in a faster way Bologna and Flor-ence. It is composed of a 2,5 km twin tunnel excavated in a complex geological context, characterized by the presence of a series of surface landslides and methane gas. The gradient is 2.6 % and the minimum radius is 1’400 m. The internal diameter of the precast seg-ment lining, equivalent to the final section of the tunnel, is 13.6 m. MAIN TBM SPECIFICATIONS TBM Earth Pressure Balanced S-574 “Martina”, manufactured by Herrenknecht, has a theoretical excava-tion diameter of 15’615 mm. It is equipped with a conical shield 12.2 m long and four back-up gantries. The total length of the machine is approximately 130 m, weighing approximately 4’500 tons. The total installed power is 16’800 kW. The main drive has a diameter of 8’700 mm and has a triple axis roller type bearing equipped with a labyrinth system including 4 sealing lips. TIME SCHEDULE OF INITIAL TBM DRIVE A time schedule of the initial TBM drive is presented in the following list: •,August 25, 2011: start of the excavation of the 1st drive of the Sparvo tunnel •,October 29,2011: stop of the advance of the TBM for gear oil contamination and clogging •,October 29 to December 20, 2011: repair works on the main drive system and modifications on the conditioning system •,December 20,2011 to July 25, 2012: restart excavation of the 1st drive (north tunnel) and its breakthrough •,July 25 to November 29, 2012: 180° turning of the TBM, detailed check of the main drive seal-ing system and fixing problems on gear boxes, race ring, clamping ring and cutting wheel •,November 29,2012 to July 24, 2013: excavation of the 2nd drive (south tunnel) and its break-through •,August 2013 to July 31, 2014: disassembly of the TBM (first 4 months) and standstill of the jobsite for structural issues on precast concrete lining of the tunnel •,July 31, 2014 to March 10, 2015: inspection, dismantling and packaging of each part of the main drive (flange ring, gear box housing and main bearing). The various phases are described hereafter in detail."

Jan 1, 2016

By R. Benito

This paper describes the development of a life-of-mine schedule (LOM) for one of the world's largest known sedimentary copper-cobalt districts located in the Katanga Province, Democratic Republic of Congo (DRC). A particular feature of the Tenke Fungurume LOM schedule is the considerable number of pits/phases for scheduling, each competing to provide the best ore available to a capacity-constrained process facility. This paper discusses the LOM scheduling objectives and constraints, data preprocessing steps such as ore binning, block aggregation and clustering analysis as a scheduling aid, the mine scheduling approach and results and conclusions. Mining Engineering, 2011, Vol. 63, No. 8, pp. 39-47. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By Muhammed Şener, Ahmet Gültek

The flotation chemicals are important in mineral processing, and new progress is made in this area day by day. For sanidine purification, some commercial collectors, which can be harmful to the environment, are used. In that respect, the poly(amidoamine) (PAMAM) dendrimers, which are non-toxic for the environment, are good candidates for flotation applications. In this study, the second-generation PAMAM dendrimer was used as a collector to remove magnetite from sanidine by microflotation method, and obtained results were compared with commercial collectors. The results showed that the PAMAM dendrimer is an efficient and selective collector for magnetite. PAMAM adsorption mechanism was determined by zeta potential and FTIR spectra. According to the microflotation results, 87.76% of magnetite recovered at pH 8 by using PAMAM as a collector. It was found that the flotation recovery with the PAMAM dendrimers is similar to the Aero 704 between pH 2 and 6 but less between pH 6 and 9 and more between pH 9 and 12. All experiments were carried out five times and the standard deviation of all results was evaluated with p = 0.05 confidence interval. The second-generation PAMAM dendrimers can be an alternative flotation chemical to the commercial ones concerning usability at a wide pH range, recovery potential, and environmentally benign.

Apr 28, 2023

By John W. Barnes

In seeking cost reductions, control methods are a fertile field because they significantly affect labor and other costs. While process control in uranium mills is excellent by the evidence of high recovery, the costs seem high to those familiar with extractive operations for other metals. To some extent this high cost is inevitable, because of exacting quality control-, the technically complicated recovery processes; poor control over grade and nature of mill feed- special problems arising out of the radioactive property of the material. Practices used in uranium mills and the limitations indicated for instrumentation and automation are discussed. It is concluded that any large investment in automatic controls should be preceded by a careful study of their reliability and maintainability, and an estimate of the net income after taxes smaller plants my find it more profitable, or at least less risky, to concentrate their efforts on the possible reduction of some control problems and to development of a stable force of skilled employees. The observed experience does not inspire optimism that ore-dressing plants can be extensively automated although certain unit operations offer a challenge for improvements in instrumentation and machine design.

Jan 1, 1960

By Luttrell. G.

The profitability of coal mining operations is highly dependent on the performance of the coal blending and processing facilities. Many companies have recognized this fact and have instituted optimization programs that require large amounts of coal characterization data, extensive operational information and complex costing models. Unfortunately, this brute force approach to optimization is often overwhelming in terms of time and cost and is generally too inaccurate to be of value in day-to-day field operations. A simpler and more practical approach involves the use of ?micro-price? optimization throughout the coal supply chain. This fundamental concept assigns unit values to each type product (particle or groups of particles) passing through the production units. True optimization occurs whenever all particles with positive worth are recovered and passed to market, while all particles with negative worth are rejected. This paper describes the fundamental workings of the micro-price concept as applied to coal blending and processing operations. Several examples are also included to demonstrate the economic gains that can be realized via the application of this concept.

Feb 23, 2014

By L. H. Pye

For large mining sites in the west, the traditional method for performing an ecological risk assessment (ERA) provides little useful information for risk managers faced with selecting and designing sound remedial options. Current U.S. Environmental Protection Agency (EPA) risk assessment guidance largely supports quantitative risk characterization of individual species as surrogates for population and ecosystem-level effects. Developing a work plan for investigating and remediating ecosystem-level changes potentially caused by large-scale historic mining/smelting contaminant release requires a decision process that incorporates a more holistic ecosystem management approach. Some of the most wasteful efforts associated with mine site ecological risk assessments arise when the risk analysis and data collection programs are not specifically linked up-front to the risk manager's decision needs. The following paper discusses the importance of employing a decision-based, ecosystem management framework when conducting ecological risk assessments at large mining sites. A case study of an ecological risk assessment currently being performed at a large New Mexico copper mine site is presented.

Jan 1, 1999

The Waste Isolation Pilot Plant (WIPP) is adding a third fan to operate in parallel with, and supplement, its two existing main fans. An engineering analysis conducted in 1995 identified the need for improved system availability and efficiency. The WIPP, located near Carlsbad, New Mexico, is a U.S. Department of Energy (DOE) Carlsbad Area Office facility designed to permanently dispose of U.S. defense-generated transuranic waste in a deep bedded salt deposit. Engineers at the WIPP performed a feasibility analysis for either modifying, supplementing, or replacing its two main mine fans. Since the centrifugal fans were installed in 1988, multiple operational and performance concerns have been identified. A comprehensive engineering study was conducted (K. McDaniel, et al., 1997) to: identify and quantify operational concerns, evaluate possible alternatives, and recommend an optimum solution. The study indicated that adding a third single-duty centrifugal fan similar to the two existing fans, and equipping that fan with Inlet Van Controls (IVCs) was the best choice. This alternative provided the most desirable combination of operational readiness, and improving system performance. The fan installation project accommodates several operational and scheduling constraints. WIPP is scheduled to receive waste in May 1998. This milestone is proceeded by an operational readiness review. Fan installation could not be allowed to compromise the WIPP's ability to declare facility readiness and had to minimize operational disruptions during the system tie-in. All engineering for the project is completed and physical modifications started in July 1997. The project will be completed in early 1998.

Jan 1, 1998

By Jörg Holzhäuser, Matthew Crow

An 18.5 km (12 mile) long tunnel is being driven by four Earth Pressure Balance Tunnel Boring Machines (EPB-TBMs) of 4.7 m (15.5 ft.) diameter through alluvial sand, gravel, silt and clay above and below the groundwater table in Los Angeles beneath buildings, railroads, freeways and the L.A. River. Continuous automatic data recording of TBM operation and field inspectors' records, accompanied by monitoring of 5,000 surface reference points and 268 borehole extensometers were used to obtain information. The paper explains the reason for selecting the method of EPB-tunneling to ensure stability of the tunnel and meeting of environmental requirements, and presents data collected to monitor and demonstrate the performance of the TBM sin the different ground conditions encountered.

Jan 1, 2003

By Danqing Gao, Brijes Mishra

Spatial variance of rock properties is an important characteristic of rock which addresses the heterogeneity of mechanical and physical properties and their effect on underground mining. Assessing spatial variance can be useful for both locating potential difficult grounds and performing reliability analysis in the mining support system. This study shows a microscale numerical model for rock material based on continuum mechanics. To consider the spatial correlation factor of mechanical properties in realistic rock mass, this study introduces a spatial correlation concept into the traditional type III extreme value distribution model. Based on the improved microscale random model, we conducted a series of numerical uniaxial compressive tests and one longwall mine model to investigate the progressive failure of rock. The results show that spatial correlation factor can significantly affect the load-deformation curves and fracture patterns. The spatial variance model was applied to a longwall mine that included several cutting sequences to observe the influence of the spatial variance on roof behavior. The cohesion and friction random fields induced failure that propagated randomly through the immediate roof in different entries. The results showed that the spatial variance provides an accurate prediction of erratic roof falls in coal mines.

Jul 20, 2020

By R. Scheffel, R. Washnock, G. Zarate

"The second survey of global copper leaching operations has been completed, the data published in 1998 has been updated. A survey questionnaire was sent to 40 identified copper leach operations around the world including those leach properties still in operation that responded to the 1998 survey. This paper lists the results of 26 operations that responded to the survey. Selected information from the survey is represented in graphical form. INTRODUCTION Copper leaching was first performed by truck dumping huge monolithic stockpiles of ore and flooding the surface with leach solution or lixiviant with little understanding to the parameters that support optimum recovery of the metal. Heap leaching has evolved into a controlled process whereby a complex low grade ore is stacked in shallow lifts (under 10 m in most cases). The ore is usually crushed and agglomerated, conveyor stacked on an engineered containment system (leach pad) and irrigated in a controlled manner. The lixiviant chemistry is designed to extract the optimum amount of metal from the ore. At first glance, heap leaching appears to be simple in nature. In fact, it is a very complex process. A plethora of technologies such as material handling, environmental control, analytical techniques, solution chemistry, hydrology and many others contribute to the design and operation of a heap leach. Heap leaching requires an inter-disciplinary approach between geologists, mining engineers and metallurgists. Many operational factors affect heap leaching. The process must address climatic factors, flexible operation, quality control before and after leaching, physical characteristics of the ore, geology, mineralogy, reagent consumption, solution application rate and methods (wobblers or emitters), particle size, and favorable conditions for bacterial growth and survival. Predicting, troubleshooting, and optimization of leach recovery is a significant challenge when considering the number of variables involved and their interactions The survey updates many of these key operating parameters to the current state of the art. It should provide the reader an excellent benchmarking summary of these factors on a site-by-site basis."

Jan 1, 2016

By M. G. Vieira

This investigation addressed the possibility of producing pellet feed at a silica content of = 1.0% using a representative sample of Samarco´s mechanical flotation tailings. This sample contained 11.0% Fe and presented an F80 = 116 µm and a d50 = 63 µm. The higher silica content was verified in the coarser fractions and the higher iron content in the fraction -37 µm. Specular hematite is the most abundant mineralogical phase in the fraction -37 µm. The technological tests used one of four methods: magnetic concentration using a wet high-intensity magnetic separator, magnetic concentration using a SLon high-gradient magnetic separator, reverse flotation or direct flotation. The methods using the magnetic concentrator SLon, reverse flotation and direct flotation did not present results meeting the target of the study: iron content in the concentrate (rougher stage) greater than 34% or iron recovery greater than 80%. Cleaner stages were not achievable with the resulting concentrates. In contrast, the most successful method consisted of using wet high-intensity magnetic separators (WHIMS) as a rougher stage and reverse flotation as a cleaner stage. Using this route, it was possible to produce a pellet feed with a silica grade of 1.0% and high specular hematite content.

Jan 1, 2010

By G. Deschênes

In an earlier study (Deschênes et al., 2009), gold and silver were shown to be efficiently extracted from samples taken from the Kupol Mine in Russia using lead nitrate in a cyanide leach system. In the current study, a com-parison of the technical and economic merits of a new technology called CANMET enhanced leaching process (CELP) was made with the cyanidation/acidification-volatilization-recycling (AVR) process using eight metal-lurgical variability samples, as well as a large composite sample, which was to represent the initial two years of Kupol mill feed. The composite sample leach feed assayed 33.4 g/t Au and 289 g/t Ag. The metallurgical results from the large composite sample demonstrated that CELP produced very similar gold and slightly higher silver leach extractions compared to the conventional cyanidation/AVR leach conditions at 1/2 the cyanide concentra-tion (1,000 ppm NaCN in CELP vs. 2,000 ppm for cyanidation/AVR leach conditions). It was estimated that the total cost per ton was approximately the same for the two technologies (total cost of CELP with the use of Merrill-Crowe at $46.48/t, with cyanidation/AVR at $46.13/t). However, the implementation of CELP would eliminate a capital expenditure of approximately $5 million for an AVR system based on a 2005 feasibility level cost estimate. Eight variability samples used to confirm the composite sample results showed that, on average, the gold leach extractions with CELP and the conventional leach conditions were very similar, but the average silver leach extraction was 2.1% higher for CELP. Furthermore, CELP silver leach extraction was 4.6% higher on average compared to conventional cyanidation for the four mid-grade variability samples evaluated. The decision was made to remove AVR cyanide recovery from the flowsheet and implement CELP at Kupol. The ability to use the conventional leach equipment with CELP and simplify the flowsheet was also a factor, given the remote location of the Kupol Mine.

Jan 1, 2010

By B. Holen, J. R. Baregi, J. A. Organiscak, A. B. Cecala

The National Institute for Occupational Safety and Health (NIOSH) cooperated with 3M Company in the design and testing of a new environmentally controlled primary crusher operator booth at the company’s Wausau granite quarry near Wausau, WI. This quarry had an older crusher booth without a central heating, ventilation and air conditioning (HVAC) system, and without an air filtration and pressurization system. A new replacement operator booth was designed and installed by 3M based on design considerations from past NIOSH research on enclosed cab filtration systems. NIOSH conducted pre-testing of the old booth and post-testing of the new booth to assess the new filtration and pressurization system’s effectiveness in controlling airborne dusts and particulates. The booth’s dust and particulate control effectiveness is described by its protection factor, expressed as a ratio of the outside to inside concentrations measured during testing. Results indicate that the old booth provided negligible airborne respirable dust protection and low particulate protection from the outside environment. The newly installed booth provided average respirable dust protection factors from 2 to 25 over five shifts of dust sampling with occasional worker ingress and egress from the booth, allowing some unfiltered contaminants to enter the enclosure. Shorter-term particle count testing outside and inside the booth under near-steady-state conditions, with no workers entering or exiting the booth, resulted in protection factors from 35 to 127 on 0.3- to 1.0-µm respirable size particulates under various HVAC airflow operating conditions.

Jan 1, 2015

By Turker Hudaverdi, Yasar Agan

This study tries to predict blast-induced flyrock using intelligent modelling techniques. Flyrock is a site-specific phenomenon. Design variables and rock properties highly influence flyrock throw distance. Site investigations were conducted in a sandstone quarry. Fundamental operational parameters, blast dimensions, bench face condition, and rock mass structure were monitored. Stepwise regression technique was applied for variable selection. Burden–hole diameter ratio, in situ block size, and powder factor were determined as the most significant parameters. Considering output of stepwise regression, artificial neural network, ANFIS, and Gaussian process regression techniques were applied to predict flyrock throw. A comprehensive validation was performed using twelve different performance indices. Pre-determination of input parameters supported development of successful soft computing applications. Rock block size was found to be an appropriate input variable for flyrock modelling. In addition to classical performance indices, standardized and symmetric accuracy metrics were quite useful in model validation process. The intelligent models predict flyrock range with an error less than 6 m. The mean percentage errors are lower than 10%. ANFIS seems to be the best model for flyrock prediction. The calculated mean absolute error is 5.36 for ANFIS model.

Nov 12, 2023

By HASAN SERKAN GOKCEN, SERKAN CAYIRLI

The purpose of this study was to investigate the dry grindability of calcite powders in a vertically and horizontally orientable laboratory batch type stirred mill. The experimental results were evaluated using stress intensity analysis. The performance was also compared in terms of mill orientation. The results showed that the d50 values decreased with increasing stress energy down to a certain point and then increased for both milling orientations. Even though the optimum stress energies for both vertical and horizontal orientations were in the range of 1*10−3 to 5*10−3 Nm at 750 and 1500 kJ/kg energy consumption, the product size was finer for the horizontal orientation at the same stress energy value. Additionally, to the best of the authors’ knowledge, this is the first study to compare mill orientation (vertical vs. horizontal) for the same mill and under the same test conditions.

Apr 21, 2021

By E. Stemn

Incident investigation is of utmost importance in most high-risk industries. This study was undertaken to study the content of past investigation reports to determine the effectiveness of the incident investigations. The study uses a semi-quantitative method to assess the effectiveness of incident investigations in the Ghanaian mining industry by evaluating the quality of past investigation reports. The assessment tool consists of 5 elements with several indicators and rating scales for assessing the quality of an investigation report as a measure of the effectiveness of the investigation. The method was applied to 304 investigation reports of 3 Ghanaian large-scale gold mines, and the results correlated with incidence rates of the mines to determine if any relationship existed. The results showed that the mines differ significantly in the quality of their investigation reports, suggesting differences in the effectiveness of their investigations. In addition, the incidence rates of the mines negatively correlated with some elements of the assessment tool. In general, the method was found useful and revealed areas where improvement is needed. INTRODUCTION The importance of learning from incidents is well documented in the literature. For instance, some scholars regard learning from incidents as important for improving safety [1,2]. Thus, many organisations spend considerable resources in identifying lessons from incidents and subsequently on the process of improvement that follows the identification of lessons. It is therefore important for such organisations to determine the effectiveness of their learning from incidents processes, in order to identify specific areas where improvements are needed, so that interventions can be as specific as possible. The learning from incidents process models the plan-act-check-do approach of management systems, often consisting of four major stages, namely; data collection and incident analysis, planning interventions, implementing interventions and follow-ups and evaluation [3,2]. The investigating and analysis of incidents have been regarded as one of the vital stages of the learning process since it is the stage where lessons are identified [3,2,4]. It has also been noted elsewhere in the literature that results of the previous stage of the learning process are important for the next stage [3]. For example, ineffective incident analyses could result in the planning of ineffective remedial measures. One of the primary aims of incident investigations is to identify lessons from previous incidents which when implemented can prevent future recurrences or minimise the effects of future incidents. There is thus the need for organisations to assess the quality of their investigations periodically since it is one of the means they adopt to improve safety and the quality of remedial measures to some extent depends on the effectiveness of the investigations. Although previous studies [5,2] have assessed the effectiveness of the learning process, and some aspects of the learning process, such as incidents reporting, there is less focus on the effectiveness of incident investigations. The research described in this paper was therefore conducted to contribute to this gap, focusing more closely on incident investigation reports.

Jan 1, 2019

By C. J. Bise, M. F. Sindelar

Regulations, such as the MINER Act of 2006, require the installation of redundant and secondary communication systems to assure that contact can be established with coal miners who may become trapped underground as a result of an event such as a fire, explosion or inundation. For half a century, the orientation towards underground communications has been that more complex systems better serve the coal miner. However, if a goal is to provide for an alternative means of establishing communication between the surface and trapped miners underground, then some of the technology employed should be simple, reliable and cost-effective. Coal mines spend hundreds of thousands of dollars on exploratory drillholes to characterize reserves, sometimes decades ahead of mine development. During the pre-mine planning phases, certain exploratory drillholes could be located and then outfitted with a simple communication link that would remain compatible with the continuing evolution of communication systems. Inexpensive links, whose locations would be accurately recorded, would be exposed by continuous miners during mine entry development, thereby allowing an underground phone to be connected to a surface station in the event of an emergency. A latent network of these communication links could be installed for less than $500 each, minimally affecting drilling and grouting operations, and could be designed to be compatible with many communication devices. This research examines methods and materials for incorporating an embedded communication link during pre-mine exploration drilling, addresses significant factors affecting its implementation, and presents a recommended design. Since mine plans are known to change, the objective is to minimize cost so that, if not used, the investment is minimal for a potential secondary means of communication between the surface and underground workings.

Jan 1, 2014

By Langtry E. Lynd

Ilmenite concentrates prepared from beach and dune sands of Florida, India, Australia, and other localities deviate to varying degrees from the theoretical composition of pure ilmenite, and generally contain more Ti02 than the formula FeTiO3 would indicate, and some Fe203. This variation in composition is due to different amounts of altered ilmenite in the concentrates.(l) The alteration has been shown to take place by oxidation and leaching of the iron in ilmenite, to yield residual products consisting of amorphous or very finely crystalline titanium dioxide and ferric oxide, Other studies (2) have stressed that ilmenite may alter first to an amorphous titanium-iron oxide, or to an amorphous mixture of titanium and iron oxides, with later alteration to crystalline titanium dioxide. There has been some speculation as to whether alteration of ilmenite is usually caused by weathering or by hydrothermal processes,(3, 4, 5) Three main methods of approach were used to study the mechanism and rate of ilmenite weathering, (1) Etch tests were used to learn the relationship between crystallographic orientation and the rate of chemical attack on ilmenite. (2) Altered ilmenites in New Jersey sands were compared with ilmenite in rocks of the area from which the sands were probably derived, (3) Experiments were carried out to determine at what rate, and by what agents, originally fresh ilmenite could be altered in the laboratory under simulated weathering conditions.

Jan 1, 1959

The engineering company's participation in quality assurance in the mining industry is twofold. Not only must it have such a program to ensure the necessary high standards for its own design and construction of a minerals processing plant, but it is also responsible as the "engineer" for both the selection and the quality of purchased equipment which goes into that plant. It is in this latter role that the engineer finds the most difficulty, or controversy, since while it is relatively easy to control his own performance, this is not ncessarily so when dealing with companies, all with their own ideas or standards. The engineer has perhaps rather reluctantly become more involved with the quality assurance of purchased equipment. This is because he has been used to writing performance type specifications and expecting the equipment manufacturer to provide the degree of quality, and control of that quality, for the product to meet the specified operating conditions. However, this has sometimes placed the manufacturer in a difficult position since to remain competitive in today's market conditions, he cannot always insist on product improvements or options which may in the long run be vital to reliable operation of the equipment.

Jan 1, 1982